# Mayor: To keep our neighborhoods clean, every street in town will be swept at least once a month. If a neighborhood n...

Zahra on July 19, 2018

Question 13

Im confused between B and D. If you request and are qualified doesn't that mean you are requesting interim sweeping? so why cant B be correct. I understand D is more precise.

Replies

Mehran on July 20, 2018

@Zahra the issue with (B) is that just because a neighborhood is qualified, it doesn't mean that the neighborhood has made a request for interim sweeping.

Compare that with (D), "A qualified neighborhood that REQUESTS an interim sweeping will have its streets swept more than once a month."

Hope that helps! Please let us know if you have any other questions.

Kanyinsola on July 3, 2019

Hi there,

I ended up choosing D but think that C could have worked as well. Could we get an explanation for why C is wrong? For context, this is my diagram

NMF > QIS
not QIS > not NMF

Request from qualified neighborhood > Satisfied
not satisfied > not qualified neighborhood

Answer c: not qualified > not swept more than once a month (not QIS > not more frequest)
swept more than once (more frequent) > qualified

Answer D: QN > swept more than once
not swept more than once > not qn that requests

- I chose D because we know that if a qualified neighborhood requests interim sweepings it'll be satisfied which means it'll be swept more than once a month. Why is C wrong? It looks like it could be traced back as well.

Ravi on July 21, 2019

@Kanyin,

Happy to help. Let's look at (C).

Here's how we can diagram the stimulus:

A diagram helps here. Street in Town - > Swept Min Once/Month
Needs More Sweepings - > Qualified Interim Sweepings
Qualified Interim Sweepings - > Request Satisfied Immediately

This doesn't really link well, but we do know from this that if a
street in town needs more than 1 sweeping per month, it'll be
qualified, and if a qualified street requests another sweeping, its
request will be satisfied immediately.

(C) says, "No street will be swept more than once a month unless it is
located in a qualified neighborhood"

This is the inverse of our diagram. We know that qualified - >extra
sweeping, but this does not mean that not qualified - >not extra
sweeping. Since it's the inverse, it definitely isn't a 'must be
true,' so we can get rid of this answer choice.

Does this make sense? Let us know if you have any other questions!